1. Field of the Invention
The present invention relates to an image forming apparatus adapted to record image on recording paper in accordance with image data read by a scanner, and also to a method and a program for controlling such an image forming apparatus. More specifically, the present invention relates to an image forming apparatus having at least one of a copying function, an image scanning function, an image transmission function, an image receiving function, and a printing function, and a storing-in-box function, and a method and a program for controlling such an image forming apparatus. The present invention also relates to an image forming apparatus having only a copying function and a method and a program for controlling such an image forming apparatus.
2. Description of the Related Art
In image forming apparatus, there is a need for a technique to reduce the time (FCOT (First Copy Time)) needed for a user to obtain a first output image. Herein, the “output image” refers to an image printed on printing paper in the case of the copying function. In the case of the image transmission function, the “output image” refers to an image transmitted to a destination. The FCOT refers to a time needed to obtain a first copied sheet after a document is set and a copy start button is pressed on an image forming apparatus. The smaller the FCOT, the higher the performance. The FCOT does not necessarily have relation to a copy time, which indicates the performance of how many sheets (with an A4 size, for example) can be copied in an unit time (PPM (pages per minutes)), but the FCOT indicates the initial time needed to start parts needed in the printing operation and thus the FCOT depends on the performance of a controller and other circuits of the image forming apparatus. By analogy to the performance of cars, the FCOT corresponds to the acceleration performance and the copy time corresponds to the maximum possible speed.
To reduce the FCOT, various techniques have been proposed. An example of such techniques is to control a process performed, by an image forming apparatus, on image data acquired via reading of a document. In general, the image forming apparatus reads image data using a reading unit and stores resultant image data in a RAM (Random Access Memory), which is capable of storing data at a high speed but which is expensive. The image data is then transferred to a hard disk which is low in storage cost per bit. When printing is performed, the image data is read from the hard disk and stored in the RAM. The image data stored in the RAM is then transferred to a printer. When a particular condition is met, image data is not stored on the hard disk but is directly transferred to the printer from the RAM to reduce the access time needed to store the image data on the hard disk and improve the FCOT (refer to, for example, Japanese Patent Laid-Open No. 2001-320561).
Another example of a technique (disclosed, for example, in Japanese Patent Laid-Open No. 2002-104695 (corresponding U.S. Pat. No. 6,529,703)) is to control the speed at which to carry printing paper in an image forming apparatus. The image forming apparatus has a photosensitive drum in a printer unit and also has a transfer unit for transferring, to printing paper, a latent image formed on the photosensitive drum by illuminating the photosensitive drum with a laser beam or a light ray emitted by an LED (Light Emitting Diode) or the like. Close to the transfer unit, a registration roller is disposed at an upstream location in a path via which printing paper is carried. The speed at which the printing paper is carried is controlled by the registration roller such that the printing paper is carried to the transfer unit at a higher speed than the speed at which the printing paper is moved when the image is transferred to the printing paper. After the printing paper reaches the transfer unit, the printing paper is moved at a speed at which an image is formed on the printing paper. By controlling the speed of the printing paper in the above-described manner, the total time needed to form the image is reduced.
In another example of a technique (Japanese Patent Laid-Open No. 11-234449), an image forming apparatus performs a reading operation and a printing operation in an asynchronous manner, that is, pre-reading of a document is performed before the printing operation is performed. This makes a multi-job practical. In this technique, when reading of documents is performed, a determination as to whether an automatic operation (of copying, transmission, storing, etc.) is possible is made in a short time even in a case in which a long time is needed to print a large number of copies.
Japanese Patent Laid-Open No. 5-336287 (corresponding U.S. Pat. No. 5,734,799) discloses a technique of displaying a preview image of image data acquired via a reading operation performed by an image forming apparatus. In this technique, the preview image has image quality similar to that of a finally printed image. Japanese Patent Laid-Open No. 2001-296784 discloses a technique in which recording paper is fed by a predetermined amount before a user presses a print start key. More specifically, in this technique, if a user makes setting or performs an operation associated with printing via a user interface before the user presses the start key, feeding of the recording paper is started and the paper is fed by the predetermined amount. That is, part of the printing operation is performed in parallel with the setting operation associated with printing.
In the above-described techniques of reducing the FCOT disclosed in Japanese Patents Laid-Open Nos. 2001-320561, 2002-104695, etc., the time of scanning, storing, reading out, and/or printing image data is reduced.
For example, in the technique disclosed in Japanese Patent Laid-Open No. 2001-320561, the time of storing and reading out image data is reduced. In the technique disclosed in Japanese Patent Laid-Open No. 2002-104695, the speed of moving printing paper to a position in the printer unit at which an image is formed on the printing paper is increased to reduce the time of printing image data. In the technique disclosed in Japanese Patent Laid-Open No. 2001-296784, printing of an image on paper is not started until particular image processing is performed and print data is produced. Therefore, in this technique, the printing operation depends on when the image processing is completed. Although this technique can reduce the FCOT compared with the technique of starting feeding paper after image processing for printing is completed, the FCOT is reduced only by an amount equal to a reduction in the time of feeding paper to the predetermined position, and thus a great reduction in the FCOT is difficult.
A processing sequence of, after settings associated with printing conditions are made, scanning a document to acquire image data of the document and printing an image in accordance with the image data is essential in an analog copying machine in which a latent image of the document is formed on a photosensitive drum using an optical unit.
A typical work flow of a process performed by a user in using a copying function is as follows. To use a multifunction machine (in particular, to use a copying function of the multifunction machine), a user first makes settings via an operation panel, including designation of whether reading should be performed in a single-sided mode or a double-sided mode, designation of whether a finishing process such as stapling or binding should be performed for an output material, designation of a scaling factor (reduction or enlargement), and designation of a layout such as a 2UP or 4UP layout (two or four pages are printed on a single sheet). After completion of the settings, reading of documents is started. Thus, it takes a rather long time before reading is started.
That is, in known image forming apparatus, reading of a document is not started until settings have been completely made and a start key is pressed by a user.